A New Method for Normalization of Capillary Pressure Curves

A new method for normalization of capillary pressure data of a reservoir was developed that incorporates the effects of pore geometry (pore size distribution index and flow zone indicator index), lithology index and irreducible water saturation. The hydraulic flow unit's approach was used to classify the reservoir formation into constant pore geometry units. The Leverett J-function was then correlated with the normalized water saturation for each reservoir unit to group the capillary pressure data of that unit into one curve. The method requires the measurements of capillary pressure, irreducible water saturation, and routine core data such as permeability and porosity. To check the validity of the proposed method, capillary pressure data, irreducible water saturations, and routine core data of a shaley-sandstone reservoir in the Gulf of Suez (Egypt) were obtained and were used in determining the accuracy of the developed equations. The calculations showed that the studied reservoir has four constant pore geometry units. An excellent agreement existed between the measured data and the calculated ones with average relative errors of - 5.8, - 4.3, 3.7 and 4.4% for flow unit-1, unit-2, unit-3 and unit-4, respectively